Sometimes when I select a group of photos to add IPTC metadata in Aperture all works well, then at other times I do the same as before with another set of photos and only the first or last photo has the IPTC data I added, the rest all show blank fields. The only way around it is by doing each shot individually. Having come back from a music festival where I shot 30 bands plus other stuff, I really don't want to do this 2591 times!!! Any idea why Aperture does this?